无接头钢丝绳绳圈生产设备的电气控制

介绍无接头钢丝绳绳圈的使用和生产状况,说明无接头钢丝绳绳圈生产设备的组成和工作过程,给出设备工作示意图,用西门子S7-200 PLC,MM440变频器和TP170B人机界面组成的控制系统,实现对该设备的控制。系统控制的关键在于缠绕绳芯的子绳能与绳芯按比例同步运行,并且退捻工字轮能随子绳小车转动一圈而旋转一周。重点介绍电气系统的控制任务、硬件组成和控制原理,给出电气控制原理图、各信号传递过程、硬件布置图和控制程序框图。运行表明该设备实现了无接头钢丝绳绳圈生产的机械化和自动化,大幅度提高了生产效率。     

三角股钢丝绳消除应力及提高质量的方法

介绍三角股钢丝绳生产的基本条件,三角股钢丝绳是在股芯的外面包捻单层或多层钢丝形成截面为三角形的股绳,其工艺参数复杂,所需的工卡具较多,而且捻制钢丝绳时必须采用翻身装置。生产方法:螺旋三角股成绳法、圆股压法。采用工字轮翻身的办法来消除钢丝绳捻制应力,工字轮翻转的方向要视钢丝绳的捻法而定;在后变形器后加定径装置以保证绳径的均匀性和准确性;成品钢丝绳必须要进行预张拉处理,消除钢丝绳捻制应力和结构伸长。根据捻股和捻绳控制要点提出提高捻制质量的方法。     

电梯钢丝绳剑麻绳芯结构和生产控制

介绍剑麻的特点,以及电梯钢丝绳用剑麻绳芯结构、剑麻纱条质量要求和捻制质量控制要点。电梯钢丝绳用剑麻绳芯结构一般分3股和4股,常用直径为4.9～12 mm,捻距为绳芯公称直径的3～3.3倍,绳芯含油率为10%～15%,纱线应经过剪毛处理,并保证绳芯每股纱条根数在3根以上,且平均捻度与要求捻度相差应不超过±5%。绳芯用油脂要同钢丝绳用油脂相同,最好选用进口高品质油脂。选用捻股合绳一次成型的先进绳芯生产设备,并严格控制生产工艺,可有效提高绳芯质量。     

钢芯钢丝绳的捻制与使用

分析6×37+IWR—17.5钢芯钢丝绳出现质量异议的原因,介绍国内钢芯钢丝绳推广应用过程中出现的问题。阐述独立绳芯结构的多样性:简单结构绳芯、复合结构绳芯、纤维包覆钢制芯、压实股与普通绳股结合绳芯。列举钢芯钢丝绳的结构特点:金属密度系数提高约17%,钢丝绳破断拉力提高,直径均匀性好,提高钢丝绳抵抗径向压力的能力,承受较大的横向压缩载荷,钢丝绳结构伸长减少,结构稳定性好,平均使用寿命提高1.2～1.3倍。介绍在提高钢芯钢丝绳使用性能方面的探索。对提高钢丝绳实物质量提出建议:重视钢芯的设计,提高钢芯的捻制质量,钢芯钢丝绳捻制过程必须自动翻身,改变钢丝绳股间处置状态。     

四股双压实钢丝绳的研发及应用

研发四股双压实钢丝绳的目的是为了替代进口的35W×K7结构钢丝绳。介绍四股双压实钢丝绳的特点,根据用户要求,将国内外不同企业的四股双压实钢丝绳各项参数进行对比研究,以K4×K36SW+FC—22钢丝绳为例,选择合理参数:钢丝绳锻打压缩率为18%,钢丝绳捻距倍数8.8,股捻距倍数6.8,股压缩率12%,由此计算出股捻距66.00～72.00 mm,绳捻距189.20～198.00 mm,纤维芯直径7.33 mm,股钢丝直径由内到外分别为2.14,1.53,1.49,1.15,1.83 mm。通过股拉轧、绳锻打生产的双压实钢丝绳整绳最小破断拉力为443.6 kN,成功应用在履带式起重机上。     

多层股钢丝绳生产用组合式成绳机研制

多层股钢丝绳由多层股交互捻制而成,通常先用SK18/500成绳机生产出绳芯,再用SK18/610成绳机捻制外层钢丝绳股,才能生产出成品钢丝绳。针对这种分步生产工艺中存在生产效率低、质量控制难的问题,将SK18/500和SK18/610捻制设备组合在一起,使绳芯和成品钢丝绳一次捻制成型。这种组合式生产方式,采用减速箱分别控制SK18/500成绳机机身转速和SK18/610成绳机机身转速,实现多层股钢丝绳内外层股绳的捻距匹配,确保钢丝绳生产质量。给出传动示意图和减速箱档位速比及电气控制方式,并将成品钢丝绳捻距与理论值对比,结果满足工艺要求。     

4V×48S+5FC—36阻旋转钢丝绳生产工艺改进

对4V×48S+5FC—36异型股钢丝绳的捻股、合绳工艺参数和制造方式进行改进。合绳成型方式由用专门辊压装置对圆股钢丝绳进行挤压成型改为在线锻打成型,股绳的捻距倍数由7.3改为7.8,钢丝绳捻距倍数由7.8改为8.3。按照绳和股的捻距倍数计算各层钢丝的直径,纤维绳芯公称直径与钢丝绳公称直径比为0.305~0.325。结果表明,合绳成型方式由辊压改为锻打后,钢丝绳的抗旋转性能、直径的通条性均得到很大改善,缩小了绳径变化范围,各股的成型率更加均匀,满足了客户使用要求。     

筒式股绳机的股扭转与扭转自消除

指出钢丝绳生产过程中绳芯松捻的原因是股扭转,对筒式股绳机产生股扭转的原因与扭转自消除的过程进行分析,认为利用筒式股绳机在捻制过程中的扭转自消除及有目的的绳股预扭转是行之有效的防止松捻和紧捻的措施,在筒式股绳机的摇架上不太适合安装翻身机构。     

同向捻捻法特点及对钢丝绳性能影响分析

分析同向捻钢丝绳所述特点背后原因,拓展同向捻捻法对钢丝绳其他性能影响研究,并就钢丝绳报废标准因捻法不同而允许最多断丝数存在显著差异进行研究。同向捻钢丝绳耐磨损基于股中可视钢丝与匹配滑轮(卷筒)有较大的接触面积。柔软性好基于股中钢丝与绳芯接触面积小,以及组绳同层股与股间钢丝接触面积小。疲劳性能优基于:(1)钢丝捻制变形过程性能损失小;(2)耐磨损延缓了承载钢丝截面减小速度、钢丝表面裂纹产生速度及裂纹后续扩展速度;(3)柔软性好使绳内钢丝弯曲应力小;(4)改善外层股数相对较少的2层股钢丝绳抗旋转性。结构不稳定基于钢丝绳受垂直钢丝绳轴线挤压载荷时分开趋势更强。具有较大反拨力基于丝在股中、股在绳中具有相同松捻趋势和股具有较大的加捻应力。捻法对抗旋转性影响基于:(1)单层股钢丝绳只有交互捻才具有抗旋转性;(2)层绳捻法影响各自股所在层绳旋转力矩。同向捻和混合捻钢丝绳折返后因为钢丝绳间钢丝严重交叉而不适合加工套管固接折返式索具。标准规定同向捻钢丝绳报废最多可见断丝数少于交互捻因为股间钢丝可视长度大,最多可见断丝数仅是交互捻时之半乃基于1个捻距内单根钢丝出现可视部位频数仅为交互捻时之半。     

平行捻钢丝绳结构和捻制方法探讨

介绍平行捻钢丝绳的结构、性能特点和捻制关键,指出平行捻钢丝绳具有破断拉力高、结构伸长小和钢芯使用寿命长等特点。实现股在绳中等捻距捻制是制造西鲁式、填充式、瓦林吞式3种基本结构,尤其是大规格钢丝绳的技术关键。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.